W124 Estate Trunk /rear interior lights staying on - help please!

[CJ e220 Wagon]

I've no idea why but the rear lights which are meant to come on when the boot or rear doors are opened have decided to remain on no matter what I do with the switch or the doors.

Now FYI, my boot lock motor no longer works, if that helps.

At the moment, I have to open the bonnet, lock the car, remove the C fuse which kills the rear lights and the locking. no perfect!

All advice will be very gratefully received. I'd much rather fix it myself then pay someone else...

Many thanks

Colin.

 

[jaymanek]

so its the switch in the motor thinking the boot is still open? have you got water in the motor mech?

 

[CJ e220 Wagon]

There was a bit of moisture but not any more.

I've stripped it down and sprayed switch cleaner on everything. No change.

Disconnected every multiplug I could find in the tailgate and still no change!

 

[mattc]

as luck would have it Television emailed me the fault find on this teh other day. PM me your email and i will send you copy

matt

p.s. you have got the selector switch for this function in the right position havenot you? i know that might seem a bit insulting but do need to check

 

[Diesel Benz]

as luck would have it Television emailed me the fault find on this teh other day. PM me your email and i will send you copy

matt

p.s. you have got the selector switch for this function in the right position havenot you? i know that might seem a bit insulting but do need to check

So there is a selector switch? I didn't dare to post on that, too long since I've had an S124 wagon (but I remember fixing the tail gate closing assist system, just don't remember what it was, it is 10, or is it closer to 20 years ago).

Anyway, why not take the bulb out as long as there is no resolution?

 

[mattc]

its a switch to the right on the centre console above the air flow selector switch (windscreen, footwell, etc). 3 position switch. top is permanently on, middle lights up on rear door or tailgate opening bottom is permanently off.

have sent mail to OP,

 

[Diesel Benz]

its a switch to the right on the centre console above the air flow selector switch (windscreen, footwell, etc). 3 position switch. top is permanently on, middle lights up on rear door or tailgate opening bottom is permanently off.

have sent mail to OP,

OK, I thought the wagon had a switch at the rear too where one could switch the light on permanently. Perhaps it was on wife's car

 

[CJ e220 Wagon]

Got the fix from Matt - thanks.

This describes how to test and replace either of the 2 micro switches in the mechanism.

As I have unplugged these, and observed no change then I must conclude that they are ok.

The dash switch does nothing now either.

This leads me to believe that there must be a wiring break in the rubber grommits leading from the roof to the tailgate. Nightmare job!

Reason I think this is that last year I had a failure of the rear wiper and washer and it was traced to a break in this wiring. The lights played up a bit and then fixed them selves. Also the lock mech died slowly - worked a bit, didn't a bit - until it finally went dead.

Sounds like this is another symptom of the flawed design of this wiring harness.

Does anyone have another suggestion or am i thinking along the right lines?

Taking out the bulb would be a short term fix - but there are 4 of the suckers....rather leave them and fix the fault.

 

[Diesel Benz]

Taking out the bulb would be a short term fix - but there are 4 of the suckers....rather leave them and fix the fault.

I was not considering leaving it unfixed but now if it is likely a wiring harness issue, it might not get even temporarily fixed by taking the bulbs out.

I hope you get good advice although you seem to be well on spot on your own already.

 

[CJ e220 Wagon]

Anyone know where I can get the wiring diagrams for my car?

 

[mattc]

Sorry that did not do the trick for you Colin; will scan my wiring diagrams and email them to you tomorrow at work (yes, very busy at the moment ) (or PM Television and see whether Malcolm can help)

i would invest in a Haynes and a Brooklands manual ASAP.

matt

 

[mattc]

just a thought; could the switch on dash have failed in an "open" position? over to the electronic experts

 

[television]

Micro switch can and do behave and wear in certain ways, you can take them out and operate them and they seem fine, put them back and you are back to square one, the switch making the click is no test for continuity

 

[230K]

Hi

It is actually quite easy to get to the wires going into the tailgate. The most of them run down the passenger side rubber tube. Undo the plastic shroud across the back of the roof and there are 12 or 14 screwed connectors. If you take the cover off the tail gate you could experiment by running a wire straight to the lock to eliminate the problem wire/wires. The dash switches do give probs too though.

230k

 

[bolide]

I strongly suspect the problem lies in the electric locking mechanism as I believe this has the light switch in it. I'd start there

The wires do crack going through the tube by the hinge but I'd start with the lock mechanism as it's easier to get at

Nick Froome
www.w124.co.uk

 

[television]

I strongly suspect the problem lies in the electric locking mechanism as I believe this has the light switch in it. I'd start there

The wires do crack going through the tube by the hinge but I'd start with the lock mechanism as it's easier to get at

Nick Froome
www.w124.co.uk

If you would like the switch details I have it loaded in my Email out box

 

[Diesel Benz]

Hi

It is actually quite easy to get to the wires going into the tailgate. The most of them run down the passenger side rubber tube. Undo the plastic shroud across the back of the roof and there are 12 or 14 screwed connectors. If you take the cover off the tail gate you could experiment by running a wire straight to the lock to eliminate the problem wire/wires. The dash switches do give probs too though.

230k

I was just reading another forum where an owner was asking help for a non-functional rear window wiper. The comment was that the wiring fails at the tailgate quite often. I would then consider this advice pretty useful.